Cable



Feb. 6, 1934.

C. P. BRODHUN CABLE Filed Sept, 24. 19,30

UNITED STATES PATENT OFFICE CABLE Carl P. Brodhun, Wilkes-Barre, Pa.

Application September 24, 1930 Serial No. 484,217

2 Claims. (Cl. 173-267) This invention relates in general to cables,desirable as substitutes for overhead wires, that and more particularlyhas reference to an armor the cost of practical installations has oftenrenfor insulated electric cables. dered the use of such practicallyprohibitive, if

The present application is a continuation in armored with metal orenclosed in conduits as 5 part of my prior copending application, Serialhas usually been found necessary for a perma.- 00

No. 307,171, filed on September 20, 1928, for nent installation. Fromthe utility standpoint, cables, which has resulted in Patent No.1,900,041, further, the metalllo SheathS by reason of the issued March'7, 1933. presence of metal in the magnetic field of the Previous tothis time, as is set forth in my conductor impeding the passage ofalternating lo aforementioned prior application, electric cablescurrents therethrough, plaotioally negative the 55 of the character Iseek to produce, adapted for advantages f an underground Cable, aSoomunderground 0r submarine installation, have pared with the ordinarilyless desirable overhead generally been encased in a metallic armor.installations.

Such armor as bands of steel wound-around the In my parent application,Serial N0 139,117,

l cable, or a lead sheath, or both, have been einfiled May 5, 19211ClSCloSe a non-magnetic. Ilon- 70 ployed to protect the conductoragainst aoeimetallic armor as a substitute for metallic armor, dental ormechanical injury. Wrappings of adapted to eliminate the disadvantagesinherent waterproofed textile protective coverings to rein a metalarmored Cable, Without appreoiably sist the deleterious effects ofexposure have also Saorifiong any of the proteotiVe qualities of a beenemployed, usually wound both under and metal armor, and in suchelimination provide for 75 over the metallic armor. a verymaterial'decrease in the cost of the manu- Notwithstanding suchprotective coverings, it facture and utility of Suolo Cableshas oftenbeen found necessary in the post to In my first application I enumerateda numadditionally protect the conductor 0f a cable by ber of materialscapable of substitution for the enclosing the same in terra cotta, wood,or metal metal windings formerly employed to armor ca- 80 conduits, orby providing even other coverings, bles to decrease the cost andincrease the einor combinations of one or more of these, in an Cenoythereof. AS iS Set forth in my later apattempt to -prolong theA utilityof such cables. plieaton, 0f Whoh the present application iS a Withparticular reference to the metallic Continuation in part, I prefer toemploy layers sheaths by which it has been sought to protect of Stripsof any Suitable rubber Compound, hav- 85 such cables, the use of thesame has been demoning the ingredients entering into the compositionstrated to be disadvantageous due to the wellthereof of such a characterthat the rubber strip known disturbances which are set up by extraneisadapted to afford substantially the same proous metal in close proximityto a conductor of tection as would a metal strip. Thus themagalternating currents. This is occasioned by the netic disturbancesresulting from the use of metal 90 fact that alternating current isimpeded by the may be eliminated, and the cost of manufacture presenceof metal in the magnetic eld of a conas well as the Weight of a cable ofthe saine charduCtO thefe0facter considerably reduced.

Disturbances of this character have been found In the use 0f an armorconsisting of Such rub- 4o to be so pronounced in many cables of thischarber strips, however, I found that While a more 95 acter that 1t hasbeen necessary to discard the highly desirable Cable was produced thanany same as unsuitable for use in carrying loads apf 1 bt d th t h-le thbb preaching those of what would be the normally Ormery o amed an a W le ru er rated capacity The economic feature has also Strips apparentlyaffprd the best subs-titte for 5, necessarily entered into theinstallation of such metal that ertam dlSaFYant.ages Obtain by rea"cables, particularly as substitutes for overhead son of partlculaljquahtles Inherent m rubber wires where a multiplicity of coveringsincluding Compounds partlcuiay the tendency. O.f the metallic armoryconduits or both have been used same to crack. Manifestly this may beeliminated to enclose the cables. In such instances the cost by'increasing the elasticity of the rubber but this 0 involved in theproduction and installation of is undesirable inasmuch as tough aComposition 105 Such Cables has Often made A@he use of other of rubberas can practically be obtained without types of conductors moredesirable. cracking is that most desirable. In ordery to It wi11 be seenfrom the foregoing that it has, overcome this disadvantage, I haveprovided for therefore, been the experience in the past, thatreinforcing the rubber StripS So that the Same while the use ofunderground cables is highly may be exceedingly tough in composition asis llo desirable, without cracking of the same resulting, as will bedisclosed herein.

The ordinary type of cable now in use has generally consistedessentially of one or more conductors suitably insulated, usually withjoint or separate coatings of vulcanized rubber, covered with a wrappingof helically wound woven fabric strips, and provided with an outercovering of jute cord helically wound around the fabric strips. Armoredcables have usually had a plu-u rality of metal strips helically woundin staggered relation over the woven fabric strips, with a supplementalor cushion winding of jute cord helically wound therebetween, In someinstances the fabric wrapping has been encased in the continuous sheathof lead or other metal. The fabric and jute cord windings have usuallybeen impreghated with suitable compounds to increase the life of thesame and prevent access of moisture.

I construct my cable in accordance with any,

of these conventional forms, except that I substitute for the metallicstrips forming the armor, armor of non-magnetic, non-metallic material,preferably as has been previously stated, rubber strips of suchcomposition that the same are as tough as can be practically obtainedwithout cracking when Wound around the cable or when the cable isflexed.

The present invention, consists in general of the provision of anelectric cable intended pri marily for underground insulations, althoughthe same is adaptable to submarine or aerial use, in which the metalarmor heretofore employed is eliminated and rubber strips substitutedtherefor. I reinforce the rubber strips employed to allow a compositionof maximum toughness being used without the likelihood of cracking. Therubber strips have been found to resist the delel terlous effects ofexposure and mechanical injury with greater effectiveness than theformer metallic armor cables, and allows for a decrease in the cost ofthe manufacture and weight of cables of this character. The electricaldisturbances resulting from the use of metal are also elimihated.

An object of this invention is to provide an electric cable having anarmor of extreme strength and durability.

Another object of this invention is to provide an electric cable havinga non-magnetic and non-metallic armor.

Still another object of my invention is to provide a non-metallic armorwhich is reinforced to give sufficient strength.

Yet another object of this invention is to provide an electric cablehaving an armor composed of helically wound strips of material sopositioned relatively to each other as to afford fluid-tight protectivecovering for the cable.

With these and other objects in view, which may be apparent herefroni,:my invention con slsts in the parts and combinations hei-cina set forthand claimed, with the distinct undering the subject matter of myinvention are shown as substituted for the former metallic strips.

Figure 2 is a top'sectional view taken on line 2-2 of Figure 1.

Figure 3 is a sectional view of one of the rubber strips showing thestrands of material longitudinally embedded therein.

Figure 4 is a perspective View of one of the rubber strips shown with aseries of parallel wires arranged in the same plane and longitudinallyembedded therein.

Figure 5 is a perspective View showing strands of textile materialsubstituted for the Wire shown in Figure 4.

Referring more particularly by numerals to the drawing, there is shownin Figure l a cable consisting of a central electric conductor l,composed of any suitable highly conductive metal such, for example, ascopper. The conductor is encased in suitable insulating material 2,which I prefer to be the ordinary continuous vulcanized rubber sheath,although any other desirable insulating medium may be employed. AWrapping of waterm proofed braided fabric strip 3 is helically woundaround the insulator sheath 2.

A jute cord 4 is helically wound around the tape or braid of impregnatedWoven fabric 3, or the layer 3 may be dispensed with entirely, if founddesirable, and the jute cord wound directly around the insulatingmaterial 2. The jute cord is preferably thoroughly Waterproofed with asate uration of asphaltum compound, parailin or any other suitableimpregnant. The Winding of jute cord 4 is adapted to protect theinsulating layer 2 and the fabric winding 3 if this is employed. Ofcourse other suitable material may be substituted for the jute cordherein set forth. This fabric Winding is primarily intended for thepurpose of affording additional insulation and protection to theconductor 1 and insulation 2, and under certain circumstances may takesome form other than a helically wound strip. It is desirable that thiscover be impregnated with a suitable waterproofing medium such as anasphaltum compound, parafn, or some other conventional water-proofingsubstance.

To afford still further insulation and protection for the conductor andthe elements 2 and I provide a layer of material Ll. as shown, thispreferably is a winding of cord thoroughly iin-- pregnated with awater-proofing compound, such, for example, as mentioned above. Ol'course, some other material may be substituted for the jute cord hereinset forth. Should the insulation be dispensed with, the cord 'l, or itssubstitute will be applied directly on the insulating material 2.

The cord. 1l also serves as a cusl'iion or pad lor novel protectivearmor to be hereinafter de scribed.

ll have found that a rubber compound which is suitably reinforcedpossesses these desired cl acteristics. The compound may l le ercoilibined with an approp, rubberized fabric, :lle waterproof armor inatci for the rubber componen 'li a :material does not inte electriccurrent passing ductor l. llt 'the saine time, this i to forni a closefitting an." protective covering :for the cables. st and durability oi?this ma te.. nereased by the reinforcing n Il lill at the same time donot seriously affect the resiliency of the armor.

While the armor may be applied in a variety of forms, I prefer thatstrips of the armor material be tightly wound about the cord 4. There istherefore shown in the drawing a strip 5 of my preferred armor material,which is shown wrapped upon the cable in the form of a helix. Mymaterial is particularly adapted for a strip armor because theresiliency of the rubber compound insures a tight t, both with respectto the jute cord 4 and the abutting sides of the stripitself. It isdesirable that the strip 5 be so wound upon the cable that the completedhelical strip be, in eiect, 'an integral sheath.

In order to avoid any possible seepage of water or moisture through thejoints formed by the abutting sides of the strip 5, I have provided anauxiliary strip 6 which is preferably similar in all respects to strip5. Under certain circumstances, however, this strip may be modified tomeet the exigencies of any given situation. The strip 6 is preferablywrapped upon strip 5 and in the same direction as strip 5. Strip 6 is sopositioned as to directly fall over the joints formed by the abuttingsides of the cable 5. The helical vjoints of strips 5 and 6 are,therefore, staggered with respect to each other, and practicallyeliminate the possibility of moisture seeping into the innermostelements of the cable.

The reinforcing means for th armor are shown more particularly inFigures 3, 4 and 5. If the armor is applied in the form of strips, Iprefer that the reinforcement be a plurality of wires or otherreinforcing means which are embedded in the rubber compound. These wiresor reinforcements may run longitudinally of the strip, and this is mypreferred embodiment. Thev mav, however, under certain conditions, beplaceddiagonally or transversely -in the strip, if a particularsituation so requires. Of course, if the armor is applied in the form ofa sheath, the reinforcements may run longitudinally of the cable, or maybe helically embedded in the sheath, or take the form o f a plurality ofannuluses.

The reinforcements 8 depicted in 4Figure 4 are a plurality of metalwires embedded in the strip 5 and running longitudinally o f the strip.The amount of metal in these wires is not sufcient to seriously impedethe current, and furthermore they are preferably formed of a metal oflow magnetic value such as zinc or lead.

In Figure 5, the reinforcements 9 are a series of longitudinal cords,which may be twisted or treat- 'ed to increase their strength. 'Ihe useof these It Will be noted that the use of the reinforcements in thearmor strips or sheath do not affect to any appreciable extent theresiliency of the member, and at the same time enhance the strength ofthe armor. The resiliency of the armor is particularly desirable when itis applied in the form of strips, for tight winding is facilitated whenthe material is resilient. A cable armor is therefore obtained ofincreased strength, of equal resistance, and with the tendency to chipand deteriorate eliminated.

Upon the armor which is thus placed upon the cable, there issuperimposed an outer cover which is shown in the drawing as composed ofjute cord helically wound about the armor. This cord is preferablyimpregnated with a suitable water proofing material, and inasmuch asthis cord is directly exposed, it is desirable that the impregna-- tionbe more thorough and the water-proofing medium more concentrated than isnecessary in the case of the cord 4. This exterior cover serves as aneffective seal for the entire cable, and also is a protection againstmechanical injury to the cable.

'I'here is provided by this invention a cable intended primarily forunderground use, although adapted to submarine and aerial installationsas well. My improvedcable has the strength and durability of themetal-armored cables, and at the same time eliminates `'the possibilityof interference with the electrical current. Furthermore my armor makesfor a lighter cable. The reinforcements give added strength to therubber compound without appreciably impairing its resiliency ornon-magnetic properties.

While I have shown and described the preferred embodiment of myinvention, I wish it to be understood that I do not confine myself tothe precise details of construction herein 'set forth, by way ofillustration, as it is apparent that many changes and variations may bemade therein, by those skilled in the art, without departing from thespirit of the invention, or exceeding the scope of the appended claims.l

Iclaim:

1. An electric cable comprising. a conductor having a plurality oflayers of insulating and water-proofing material therearound, and stripsof stiff bendable rubber compound having longitudinally arranged wiresembedded therein wound around the insulating material to armor thecable.

2. An electric cable comprising a conductor having a plurality of layersof insulating and waterproofing material therearound a pair of windingsthereover comprising strips of relatively stiff but bendable rubbercompound with longitudinally arranged wires embedded therein to armorthe cable and a winding of insulation and protective materialtherearound.

